1. Field of the Invention
The present invention pertains to the making of thick film circuitry and more particularly to a novel registration pattern useful in aligning screened artwork as used in printing on a ceramic substrate base.
2. Background Art
At the present time, the alignment or registration of an imaged screen to a ceramic substrate for the first layer of printing a thick film circuit onto the ceramic substrate base is a tedious and time consuming procedure. The proper alignment demands that each of the printed layers are correctly positioned relative to the edges of the substrate base. This alignment procedure is particularly time consuming when the image to be printed is located relatively distant from the edge of the substrate. In usual practice a number of attempts at correct positioning are required, each of which entails printing a blank substrate and then measuring the image location on a precision optical comparator. After such an attempt is made, the image screen may of necessity be cleaned prior to the next attempt, or any initiation of production. Such cleaning step is required because the ink or paste dries readily on the screen. Additionally, if the first attempt is not correct and another attempt is needed, the screen of course must be repositioned. It should be further noted that the detection of any inconsistencies in the pattern location requires extensive measurement on an optical comparator. Obviously if this measurement has not been made, a potentially defective product may be subjected to further processing with the additional loss of time and extensive additional cost.